First off, Cabergoline is E3D (Every Three Days), so you could take it on the day of, but you could take it two days before and be fine, it lasts in your system a while. Second, Yohimbine has profound effects on your vascular system, it tends to raise your blood pressure at a low-normal dose. Cabergoline DROPS your blood pressure. Due to the radical difference in MOA and chemical properties of both drugs, your looking at some intense effects on your heart and mind. Take Yohimbine in the Morning and Caber at night ideally, Caber is used as a muscle relaxant anyway.
Yohimbine raises prolactin, but has only moderate affinity to blocking the D2 receptor (same one that caber activates to lower prolactin), so it might or might not slow down the prolactin reduction from Caber, now, I don't know why you are using Caber, but if you haven't finished lowering prolactin (if that was ever an issue), just remember how opposite these chemicals are and yohimbine might block some of the effects of Caber in regards to prolactin antagonist.
Beware of blood pressure changes, I can see this combination really fucking with your blood pressure bro, but just be aware when doing this.
Also, 0.5mg of Caber is quite enough!
Again EVERY THREE DAYS. Not Every Day, and it doesn't matter if it's 30 mins, or 3000 minutes before sex. It does not have to be timed like Viagra or Cialis, and really it doesn't do much for your erections anyway, mostly libido.
Yohimbine should be 17 mg minimum. But you may start at 14mg if you are sensitive to stimulants, as Yohimbine is a very strong stimulant.